外部变量可通过功能访问和操作

Question

请查看以下代码。

import random
devicelist = ['a','a','a','a','a']

def generateconfig(tempconfiguration):
 global devicelist
 indexpositionzero = []
 indexpositionone = []
 for index in range(len(devicelist)):
  if tempconfiguration[index] == 1:
   indexpositionone.append(index)
  else:
   indexpositionzero.append(index)
 if len(indexpositionone) >= 3:
  godown = True
 elif len(indexpositionone) == 0:
  godown = False
 else:
  godown = random.randrange(0,2,1)
 if godown == True:
  index = random.randrange(0,len(indexpositionone),1)
  tempconfiguration[indexpositionone[index]] = 0
 if godown == False:
  index = random.randrange(0,len(indexpositionzero),1)
  tempconfiguration[indexpositionzero[index]] = 1
  return tempconfiguration

x = [1,0,1,0,1]
y = generateconfig(x)

print x
print y

运行此代码会将x更改为y的相同值。为什么会这样？我根本不碰x！这样的混乱！请帮忙。